In recent years, data transmission and reception through a communication network, especially the Internet, become widespread along with the development of digital processing devices. Among the digital processing devices which transmit and receive data through the communication network, the digital processing device designed to provide data is defined as a server and the digital processing device designed to request and receive data is defined as a client.
In order to detect or block bad traffics which gain access to a server, a network security device such as an IDS (Intrusion Detection System) or an IPS (Intrusion Protection System) can be used. In this network security device, a pattern matching card or an accelerator card which stores signature patterns can be used in order to rapidly detect signature patterns of bad traffics.
However, due to the use of simple pattern matching between a card and an analyzing engine, the conventional method is difficult to cope with patterns which grow complex and is suffering from a high erroneous detection rate.